Saving Michigan’s Coaster Brook Trout

Researchers are focused on the identity and habits of the coaster because if the fish are just common brook trout living large in a Great Lake, then one could argue there’s nothing endangered about them: there are millions of ordinary brook trout in Michigan and throughout the Great Lakes basin. “You have to keep in mind that this is a complex listing because it’s not the only brook trout in North America,” says Jack Dingledine, a Fish and Wildlife Service biologist working on the petition. “Part of what we are doing is determining whether coasters are a distinct population segment of brook trout.”

Note that Dingledine did not say “distinct species.” To gain endangered species protection, separate species status is not required. Considerations such as where and how the fish lives and its breeding habits all factor in. In fact, scientists agree that the coaster is almost certainly not a separate species, that the long-held assumption that the fish is a large brook trout is probably accurate.

Genetic science does, however, come into play, but it is not focused on, say, Is there a gene that makes the fish big? Or Is there a gene that makes the fish migrate? That would be beyond the reach of the data. But genetics can be useful in helping determine whether the Salmon Trout coasters are a distinct breeding population. Based on tissue samples that Baker and Huckins collected in August, Dr. Kim Scribner, at Michigan State University, has found there are large and significant differences at the genetic level between brook trout in the Salmon Trout river and brook trout from other Lake Superior streams. There is comparatively less genetic difference between coasters and the brook trout they live among in the Salmon Trout. There is also evidence of interbreeding among coasters and resident brook trout.

So, couldn’t biologists just dump regular brook trout in Lake Superior and just watch them grow huge? This was tried a number of times in the 20th century, but the coaster population continued to slide. Nature, it turns out, is more nuanced than that. Or, as Scribner says, “That is a naïve view of the world.” And it remains one of the other great mysteries of the coaster: what makes them grow big?

Biologists did take a more nuanced approach to coaster stocking when they planted coaster fry in five Upper Peninsula streams—not the Salmon Trout—each year from 1997 to 2002. One stocking strain was from Canada’s Nipigon River (the world’s most stable coaster population) and the other from Isle Royale.  “They’d grow and go out to the lake, but we just didn’t see them coming back as spawners,” Huckins says. A few stocked coasters were found in other streams, but if they did establish new populations it is not evident.

At this point, stocking the Salmon Trout would be “crazy” for fear of damaging the genetics of the coaster community, according to Huckins. Fish populations can become adapted to a river over the years, selected to do well under the conditions in that river. “If we stock new fish over the top of the local population, we can swamp that local population with alleles that weren’t selected for, and you would reduce the population.”

Biologists at the FWS are not, by law, allowed to tip their hand on how they will decide on the listing petition. So I call Huron Mountain Club member and attorney Dykema. He fell in love with the coaster when he caught one as a teen and, over the years, has not only raised money for the fish, but also spent time in waders helping with research. Is the coaster’s a compelling case? “It seems to me the case is very strong, if not overwhelmingly strong. But I’m also hopeful that the new administration will enforce the endangered species act.” Wishful thinking?

Rewind to early evening, that first day of sampling on the Salmon Trout. Huckins has to check a monitoring device that records water flow and temperature at the river mouth, so we jostle down the forest-dark two-track to Salmon Trout Bay and walk a mile along the sandy shore. The August sky glows a cloudless robin’s egg blue. I stand at the river mouth and take in the arc of the bay and the shimmering cobalt beyond. Huron Island floats as a barely visible dark nub on the northwest horizon. East along the shore, the giant nest of a bald eagle bulges from a towering white pine. I hear a motor from a boat I cannot see, though I can see for miles.

This is the realm of the Salmon Trout coaster. And this interface between river and lake, now at my feet, is their threshold. Genetics might determine their size, but crossing from the safety of the river to the dangers of the big water is the act that defines the coasters, that earns them their name. They live on the coast. They swim along it, hence, coaster.

And so, the final curious thing that captivates me about the coaster: how its destiny is embedded in its name. The health of the coast, the future of the coast—the coaster habitat—is what will determine the fish’s existence, endangered species listing or not. And a good, healthy coast, well, that will take many committed coaster fans to make happen.

Article Comments

  • George Van Setters

    I live in the Upper Peninsula, and fish more of the better streams in serch of this very fish and personaly beleive their simply must be more than 400 of this grand species. I fish everyday, simply it is my life, in the past 10 yrs I will say with confidence I had say close to 20 fish upwards of 16 inch’s and at least 3 closer to 20inchs at the end of my line. My focus turned to them more in the past 5yrs in which Ive seen a huge population change, which I acount for a low level period, the region is going through. I began to notice fish breaking 4lb test line and even rods in a second, so I got a little excited if you will. switched to some unorthidoc fishing methods and began to piture fish, more and more over every changing year and seriously their must be more research, I beleive this fish to be very smart, I find them in places that sometimes bewilder me on how they even got were they where. Recently I read an article on Coasters and they say’d only 1 stream in the U.P. contained coasters the salmon river, and its simply is not true! The little two heart, big two heart, and many, many, creaks, ditches, runoffs and dams have Coasters. A lot of time, and comitment and you can find them.

  • Anonymous

    Recent genetic testing has shown that “coaster” brook trout are simply stream brook trout that moved to the lake and grew bigger in that environment. They return to the streams to spawn with the brook trout that stayed there, so they really are all one species.

  • Anonymous

    My best friend’s father caught (and ate) a 22 inch “coaster” caught out of lake michigan in Menomonee within the last 5 years.

  • Anonymous

    I live in tip of the mitt Michigan. Brookies are the apple of my eye, the surroundings of their existence constitute the most beautiful places on earth. The fishing population has become too focused on entering large prolific fish to our native waterways. Salmon, steelhead, and even browns are non-native species to our waters. The commercialization of our waterways has almost kiled our native fishery. The once prolific Laker and resident Brook Trout are largely overshadowed by invasive trash species that out compete and destroy habitat. Why introduce a large pacific salmon that will travel into a brook trout stream, unsuccessfully spawn, and rot and die? This creates a huge chemical imbalance of its own in our waters. The DNR needs to receive a head from butt surgery and leave the trash fish in the pacific, allow our native species to recover, and offer an apology to mother earth. The Coasters are sacred to those that know their residences, and WE are the ones that try and save them. The government is only out for money. Period.

  • Anonymous

    Dr. Jill Leonards from northern michigan university’s research on 7 mile creek is the most up to date and factual information. Read it, support it.